Solid Milk And The Method Of Manufacturing Thereof

ABSTRACT

[Problem] The object of invention is to provide solid milk with favorable solubility and enough strength and the method of manufacturing the solid milk. [Means] The solid milk of the invention has X-ray diffraction pattern of its surface area that has a main peak of 2theta=10-15 degrees at 2theta=10-11 degrees or at 2theta=12-13 degrees. A method for the manufacture of solid milk comprises compressing powdered milk to obtain compressed powdered milk; humidifying the compressed powdered milk to obtain humidified compressed powdered milk; and drying the humidified compressed powdered milk to obtain the solid milk. A part of amorphous lactose at the surface of the solid milk  12  is crystallized at the steps of humidifying step and drying.

FIELD OF THE INVENTION

The present invention is directed to solid milk which is dissolved inhot water when the solid milk is drunk and the present invention isdirected to the method for manufacturing the solid milk. Morespecifically, the present invention relates to solid milk which haspreferred solubility and strength.

DESCRIPTION OF THE RELATED ART

Powdered milk is a food product whose life is improved by removingalmost all of the necessary moisture for the microbial growth frombovine milk and the like. Since the capacity and weight decrease byremoving moisture, the powdered milk can be easily transported. Thus,the powdered milk has advantages in life and transportation. Thepowdered milk has interspaces between milk powders, and the porosity ofthe milk powder is generally 60% to 70%, so that it readily dissolves inhot water. However, the powdered milk requires measurement of properquantity every time it is dissolved in, for example, hot water. Further,upon measurement of the powdered milk or upon taking out the powderedmilk, the powdered milk may spread. Therefore, solid milk made bypowdered milk that is solid state has been proposed (the patent document1, Japanese Utility Model Application Laid-Open Publication No.SHO49-130189, and the patent document 2, Japanese Utility ModelApplication Laid-Open Publication No. SHO61-118280). However, it has notbeen easy to actually make the powdered milk into solid state andsatisfy both of strength and solubility. Namely, even if the powderedmilk is made into solid state, it has been easy to break and has beenhard to handle. Moreover, the solid milk has smaller surface area asthat of powdered milk, and thus solid milk has less solubility in hotwater.

The patent document 3, Japanese Patent No. 4062357, discloses the methodfor manufacturing solid milk. The method compresses powdered milk,first. Then the method humidifies and dries the compressed powderedmilk. The solid milk obtained by the method has porosity of specificrange and predetermined amount of free fat. Thus the solid milk hassufficient strength and solubility. The solid milk disclosed in thedocument superior to previous solid milk. However, it is desired toprovide further progressed solid milk in a view point of solubility andstrength.

In the field of medicine, various intraoral fast disintegrable tabletsreadily soluble in the mouth have been developed

For example, the patent document 4, Japanese Patent ApplicationLaid-Open Publication No. Hei 11-012161, discloses the technique formanufacturing intraoral fast disintegrable tablets with high strength.The technique compresses medicament, a water soluble diluents andamorphous sugar and then aging the compressed ingredient so as tomanufacture such tablets by means of conventional compressor with fewsteps. The patent document 5, Japanese Patent Application Laid-OpenPublication No. Hei 11-349475, discloses the method for easily andeffectively manufacturing intraoral fast disintegrable tablets that haveenough strength to be handled under high humid circumstances and thatare dissolved in a mouth quickly. The method exposures tablets, whichhas about 5 to 40 wt % of amorphous lactose, which is compressed at lowpressure under humid circumstance with relative humidity of about 60% to90% so as to change amorphous lactose to crystalline lactose.

The patent document 6, WO 95/20380, discloses the technique tomanufacture compressed materials that has quick dissolubility in a mouthand sufficient strength to be dealt in manufacturing processes andtransporting processes. The method uses the first sugar that has quickdissolubility but low formability and the second sugar that has highformability to make tablet. The technique uses lactose and mannitol asthe first low formability sugar and it uses maltose and maltitol as thesecond high formability sugar.

However, these techniques are directed to manufacturing medicament andthe requirement and conditions are different from those of solid milk ofthe present invention. Generally speaking, medicaments contain smallamount of active ingredients. Namely, intraoral fast disintegrabletablets may comprise large amount of additives and thus it is easy tocontrol dissolubility and strength of intraoral fast disintegrabletablets. Just controlling additives, it is possible to obtain intraoralfast disintegrable tablets with high dissolubility and enough strength.Furthermore, intraoral fast disintegrable tablets do not contain fatcontrary to powdered milk. Still further a piece of intraoral fastdisintegrable tablet generally has small volume. Thus it is impossibleto utilize the technique of high dissolubility in manufacturingintraoral fast disintegrable tablets into the method of manufacturingsolid milk. The intraoral fast disintegrable tablets are required to bedissolved quickly by means of little water in a mouth. Contrarily, solidmilk is dissolved in hot water and usually is not taken directly bymouth. Thus the required dissolubility of solid milk is not high asrequired by intraoral fast disintegrable tablets. In medicament,strength of medicament may be attained by adding other ingredients topure amorphous sugar. In case of manufacturing solid milk, powdered milkis manufactured by spray dry process using liquid that comprises variouscomponents. Thus the amorphous lactose dissolves in other components toconform solid dispersion in granules. To manufacture solid milk that hassufficient strength by using such granules, which has various componentsas well as amorphous lactose, is difficult compared with makingmedicament. Thus the methods for manufacturing medicaments are notdirectly used as the method for manufacturing solid milk.

CITATION LIST Patent Literature

-   [Patent Document 1] Japanese Utility Model Application Laid-Open    Publication No. Sho 49-130189-   [Patent Document 2] Japanese Utility Model Application Laid-Open    Publication No. Sho 61-118280-   [Patent Document 3] Japanese Patent Application Laid-Open    Publication No. 4062357-   [Patent Document 4] Japanese Patent Application Laid-Open    Publication No. Hei 11-012161-   [Patent Document 5] Japanese Patent Application Laid-Open    Publication No. Hei 11-349475-   [Patent Document 6] WO 95/20380

SUMMARY OF INVENTION Problems to be Solved by the Invention

An object of the present invention is to provide solid milk that has apreferred solubility and strength and a method of making the same.

Another object of the present invention is to provide solid milk that iseasy to handle in transportation and easy to be measured, and a methodof making the same.

Another object of the present invention is to provide solid milk whosecomponent composition is controllable with only nutritional component,and a method of making the same.

Another object of the present invention is to provide a method formanufacturing solid milk that can prevent powdered milk from attachingto trays.

Another object of the present invention is to provide method of makingpowdered milk and solid milk which can make not only the powdered milkbut also the solid milk based on the powdered milk after making thepowdered milk.

Means for Solving the Problem

The present invention basically based on the following new sight thatwhen a part of amorphous lactose at the surface of solid milk iscrystallized under the predetermined condition to be crystalline lactosethen the solubility of solid milk as well as the strength of the solidmilk increase. Namely at least one of the objects is solved by thefollowing solid milk and the method for manufacturing the solid milk.

The first aspect of the present invention is directed to solid milk. Thesurface 12 of the solid milk has X-ray diffraction pattern that has amain peak of 2theta=10-15 degrees at 2theta=10-11 degrees or at2theta=12-13 degrees. The peak at the range of 2theta=10-11 degrees isconsidered to have relationship with anhydrous crystalline lactose. Thepeak at the range of 2theta=12-13 degrees is considered to haverelationship with monohydrate crystalline lactose. The main peak of2theta=10-15 degrees is at the range of 2theta=10.25-10.75 degrees or atthe range of 2theta=12.25-12.75 degrees.

The solid milk of the present invention intentionally comprisescrystalline lactose at the surface of the solid milk. Generallyspeaking, when lactose of solid milk is completely crystallized, thenthe strength of the solid milk becomes extremely high. However, thesolubility of such solid milk becomes extremely low. The presentinvention makes crystalline lactose to exist at the surface of the solidmilk such that the solubility as well as the strength of the solid milkincreases. We think that, because of the method of the presentinvention, only a part of the surface of the solid milk has crystallinelactose and then the surface of the solid milk has a hard layer that hasholes or vacant spaces. The solid milk of the present invention has highstrength because of the hard layer that has crystalline lactose.Further, when the solid milk is dissolved, hot water may enter into theholes or vacant spaces, which may be a net shaped, quickly. Thus thesolid milk has high solubility.

The Ia/Ib of a preferred embodiment of the solid milk is equal to ormore than 2.5. The Ia is a sum of:

an integrated intensity of a first region of X-ray diffraction patternof the surface 12 of the solid milk, the center of the first region is amain peak of 2theta=10-11 degrees of the pattern and the width of thefirst region is twice of the full width of half maximum of said mainpeak of 2theta=10-11 degrees; and

an integrated intensity of a second region of X-ray diffraction patternof the surface 12 of the solid milk, the center of the second region isa main peak of 2theta=12-13 degrees of the pattern and the width of thesecond region is twice of the full width of half maximum of said mainpeak of 2theta=12-13 degrees.

The Ib is a sum of:

an integrated intensity of a first region of X-ray diffraction patternof center area 11 of the solid milk, the center of the first region is amain peak of 2theta=10-11 degrees of the pattern and the width of thefirst region is twice of the full width of half maximum of said mainpeak of 2theta=10-11 degrees; and

an integrated intensity of a second region of X-ray diffraction patternof the center area 11 of the solid milk, the center of the second regionis a main peak of 2theta=12-13 degrees of the pattern and the width ofthe second region is twice of the full width of half maximum of saidmain peak of 2theta=12-13 degrees.

The preferred embodiment of the solid milk is that the amount ofcrystalline lactose at the surface 12 of the solid milk is larger thanthat of crystalline lactose at center area 11 of the solid milk. Thecrystalline lactose includes anhydrous and monohydrate form. Thepreferred embodiment of the solid milk is that the Ia/Ib is from 2.5 to15. The central area of the solid milk may have no crystalline lactose.The solid milk of the present invention has many of the crystallinelactose at its surface area and there is little crystalline lactose atthe central area of the solid milk. The feature brings the solid milk ofthe present invention superior strength and solubility.

The preferred embodiment of the solid milk is that the amount ofcrystalline lactose at the surface 12 of the solid milk is larger thanthat of crystalline lactose at center area 11 of the solid milk. Moreconcretely, a preferred embodiment of the solid milk is that wherein theamount of crystalline lactose at the surface 12 of the solid milk ismore than 5 wt % larger than that of crystalline lactose at center area11 of the solid milk. If all of the surface area of the solid milk iscrystalline lactose, the solubility of it is not preferable. Thus apreferred embodiment of the solid milk is that the amount ratio ofcrystalline lactose and amorphous lactose at the surface 12 of the solidmilk is 25:75 to 90:10.

Central area of the solid milk does not have to comprise muchcrystalline lactose. Thus a preferred embodiment of the solid milk isthat the center area 11 of the solid milk does not contain crystallinelactose. The amount rate of crystalline lactose and amorphous lactose atthe center area 11 of the solid milk may be less than 90:10, namely theweight ratio of crystalline lactose and amorphous lactose is less than1/9.

The solid milk of the present invention has crystalline lactose at thesurface area. The strength of solid milk increases when the layer thatcomprises crystalline lactose has thickness more than predeterminedvalue. Thus a preferred embodiment of the solid milk is that the solidmilk has 0.2 mm or more of a hard layer at the surface 12 of the solidmilk. The hard layer of the solid milk may comprise more than 10 wt % ofcrystalline lactose. When the solid milk has a hard layer whichcomprises crystalline lactose more than predetermined amount, the solidmilk has enough strength.

A preferred embodiment of the solid milk is that the volume of the solidmilk is from 1 cm³ to 50 cm³. This solid milk has larger volume thanthat of powdered milk and it makes easy to calculate suitable amount ofthe solid milk and it makes solid milk to be convenient to betransported.

A preferred embodiment of the solid milk is that when a force, which iscaused by a load, in the direction of short axis of the solid milkcausing the solid milk be broken is 30 N to 300 N when the solid milkhas a rectangular solid shape. The solid milk of the embodiment hassufficient strength and thus it is possible for the solid milk frombeing broken in transport. When solid milk has division line and thesolid milk has the above strength, it is possible to divide the solidmilk in accordance with the divide line.

A preferred embodiment of the solid milk is that the ingredient of thesolid milk consists only of powdered milk. The solid milk of the presentinvention is usually taken by infants or children. Thus it is preferredfor the solid milk to be manufactured without adding additives as littleas possible. This embodiment of the solid milk can attain solid milkwith excellent strength and solubility by producing crystalline lactoseat the surface area and make the crystal attached to each other eventhough no additives are added.

A preferred embodiment of the solid milk is that the solid milk isdissolved in a liquid the volume of the liquid increases 9.5 ml to 10.5ml (more specifically 10 ml) or 19.5 ml to 20.5 ml (more specifically 20ml). When someone gives milk to an infant or a child using the solidmilk, she usually pours hot water of predetermined amount into a babybottle, first. Then she adds a piece of or predetermined pieces of solidmilk into the hot water to obtain liquid milk that is given to theinfant or the child. Contrarily, she may enter the solid milk first intothe baby bottle and she might enter wrong number of solid milk when shemakes milk for the infant or the child. In such a case, if she takes thesolid milk off from the bottle, then the solid milk may suffercontamination. Furthermore, it is troublesome to take solid milk fromthe baby bottle. Thus the embodiment of the solid milk is configured toincrease a predetermined amount when it is dissolved in hot water. Thuseven if the solid milk is poured before the hot water is poured into thebaby bottle, all she has to do is to pour hot water with considering theamount that increased by the solid milk. Namely, the solid milk is veryconvenient to deal with.

The second aspect of the present invention is directed to a method forthe manufacture of solid milk. The method comprises a step ofcompressing powdered milk, a step of humidifying the compressed powderedmilk and a step of drying the humidified compressed powdered milk. Thestep of compressing powdered milk is a step for compressing powderedmilk so as to obtain solid compressed powdered milk. The step ofhumidifying the compressed powdered milk is a step for obtaininghumidified compressed powdered milk. The step of drying the humidifiedcompressed powdered milk is a step for drying the humidified compressedpowdered milk so as to obtain the solid milk. A part of amorphouslactose at the surface of the solid milk 12 is crystallized at the stepsof humidifying step and drying. The method of the present inventioncrystallizes a part of amorphous lactose at the surface area of thecompressed powdered milk. Then crystalline lactose attaches each otherand forms a hard layer that comprises vacant spaces and thus it ispossible to obtain solid milk that has suitable solubility and highstrength.

A preferred embodiment of the method for the manufacture of solid milkis that the step of humidifying is a step for keeping the compressedpowdered milk under humidity of 60% RH to 100% RH atmosphere for 5seconds to 1 hour. Another preferred embodiment of the method for themanufacture of solid milk is that the step of drying is a step forkeeping the humidified compressed powdered milk under humidity of 0% RHto 30% RH atmosphere for 0.2 minute to 2 hours. A preferred embodimentof the method for the manufacture of solid milk is that the powderedmilk comprises more than 30 wt % of lactose. A preferred embodiment ofthe method for the manufacture of solid milk is that the powdered milkcomprises more than 20 wt % of amorphous lactose. A preferred embodimentof the method for the manufacture of solid milk is that the powderedmilk does not contain any crystalline lactose or comprises less than 10wt % of crystalline lactose. When the ingredient comprises little amountof lactose crystal that forms core to crystallization it becomespossible to make large amount of amorphous lactose to change intocrystalline lactose.

A preferred embodiment of the method for the manufacture of solid milkis that the powdered milk comprises 0.5 wt % to 10 wt % of crystallinelactose or the powdered milk comprises powder of crystalline lactose.When the ingredient comprises little amount of crystalline lactose thatforms core to crystallization it becomes possible to make large amountof amorphous lactose to change into crystalline lactose.

A preferred embodiment of the method for the manufacture of solid milkis that the powdered milk obtains crystalline lactose by humidifying anddrying granules of ingredients of the powdered milk.

A preferred embodiment of the method for the manufacture of solid milkis that the method further comprises a step of cooling the concentratedmilk before the step of drying such that the powdered milk obtainscrystalline lactose. The step of drying the humidified compressedpowdered milk may be a spray dry process.

Technical Effect of the Invention

The present invention changes a part of amorphous lactose that isincluded in powdered milk and thereby it can provide solid milk that hasa preferred solubility and strength and a method of making the same.Further the present invention can provide solid milk that is easy tohandle in transportation and easy to measure and method of making thesame.

The present invention can obtain solid milk with hard surface only bythe steps of humidifying and drying such that it can control compositionof solid milk by controlling nutritional component of powdered milk. Thepresent invention can provide a method for manufacturing such solidmilk.

Another object of the present invention is to provide a method formanufacturing solid milk that can prevent powdered milk from attachingto trays during the steps of humidifying and drying by changing a partof amorphous lactose that is included in powdered milk. Thus the methodfor manufacturing solid milk of the present invention is highproductivity.

The present invention can provide a method for manufacturing solid milkthat can manufacture solid milk after manufacturing powdered milk bymaking use of the powdered milk.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of the cut surface of solid milk.

FIG. 2 is an powdered X-ray diffraction pattern that shows peaks ofcrystalline lactose.

FIG. 3 is SEM picture that shows the influence of the amount ofamorphous lactose in solid milk.

FIG. 4 is SEM picture that shows the influence of the amount ofcrystalline lactose in solid milk.

FIG. 5 is a powdered X-ray diffraction spectrum regarding the solid milkmanufactured using powdered milk 2A of example 2.

FIG. 6 is a powdered X-ray diffraction spectrum regarding the solid milkmanufactured using powdered milk 2B of example 2.

FIG. 7 is a graph that shows a relationship between the distance fromthe surface and the comprising ratio of crystalline lactose.

FIG. 8 is a graph that shows effect of attachment with various amount oflactose crystal.

FIG. 9 is a graph that shows effect of type of additives.

FIG. 10 is SEM picture that shows effect of attachment with variousamount of crystalline lactose.

BEST MODE FOR CARRYING OUT THE INVENTION

We explain the best mode for carrying out the present invention. Thefollowing embodiments are examples and thus the present inventionincludes various modifications that the skilled person may arrive at.

1. Solid Milk

FIG. 1 is a schematic diagram of the cut surface of solid milk. Elementnumeral 11 indicates the central area and element numeral 12 indicatesthe surface area. The solid milk of the present invention may comprisecrystalline lactose at the surface area. The surface 12 of the solidmilk has X-ray diffraction pattern that has a main peak of 2theta=10-15degrees at 2theta=10-11 degrees or at 2theta=12-13 degrees. The X-raydiffraction pattern may be obtained by an X-ray Powder Diffractionmeter. The peak at the range of 2theta=10-11 degrees is considered tohave relationship with anhydrous crystalline lactose. The peak at therange of 2theta=12-13 degrees is considered to have relationship withmonohydrate crystalline lactose. The main peak of 2theta=10-15 degreesis at the range of 2theta=10.25-10.75 degrees or at the range of2theta=12.25-12.75 degrees.

The preferred embodiment of the solid milk relates to the followingsolid milk.

The Ia is defined as a sum of:

an integrated intensity of a first region of X-ray diffraction patternof the surface 12 of the solid milk, the center of the first region is amain peak of 2theta=10-11 degrees of the pattern and the width of thefirst region is twice of the full width of half maximum of said mainpeak of 2theta=10-11 degrees; and

an integrated intensity of a second region of X-ray diffraction patternof the surface 12 of the solid milk, the center of the second region isa main peak of 2theta=12-13 degrees of the pattern and the width of thesecond region is twice of the full width of half maximum of said mainpeak of 2theta=12-13 degrees.

The Ib is defined as a sum of:

an integrated intensity of a first region of X-ray diffraction patternof center area 11 of the solid milk, the center of the first region is amain peak of 2theta=10-11 degrees of the pattern and the width of thefirst region is twice of the full width of half maximum of said mainpeak of 2theta=10-11 degrees; and

an integrated intensity of a second region of X-ray diffraction patternof the center area 11 of the solid milk, the center of the second regionis a main peak of 2theta=12-13 degrees of the pattern and the width ofthe second region is twice of the full width of half maximum of saidmain peak of 2theta=12-13 degrees.

The preferred embodiment of the solid milk is that the amount ofcrystalline lactose at the surface 12 of the solid milk is larger thanthat of lactose crystals at center area 11 of the solid milk. Thelactose crystal includes anhydrous crystalline lactose and monohydratecrystalline lactose. The Ia/Ib of a preferred embodiment of the solidmilk is equal to or more than 2.5. The preferred embodiment of the solidmilk is that the Ia/Ib is from 2.5 to 15. The other example of Ia/lb is3 to 10, and may be 5 to 10. The central area of the solid milk may haveno lactose crystal. The solid milk of the present invention has many ofthe crystalline lactose at its surface area and there is littlecrystalline lactose at the central area of the solid milk. The featurebrings the solid milk of the present invention superior strength andsolubility. It is preferred that 10 wt % to 75 wt % of the amorphouslactose at the surface area changed to be lactose crystal. The amount ofamorphous lactose and the amount of crystalline lactose may be measuredby the method of test example 1 whish is referred hereafter.

The preferred embodiment of the solid milk is that the amount ofcrystalline lactose at the surface 12 of the solid milk is larger thanthat of crystalline lactose at center area 11 of the solid milk. Moreconcretely, a preferred embodiment of the solid milk is that wherein theamount of crystalline lactose at the surface 12 of the solid milk ismore than 5 wt % larger than that of crystalline lactose at center area11 of the solid milk. As is shown by the working example, the amount ofcrystalline lactose at the surface 12 of the solid milk is more than 10wt %, or more than 20 wt %, or more than 25 wt % larger than that ofcrystalline lactose at center area 11 of the solid milk. If all of thesurface area of the solid milk is crystalline lactose, the solubility ofit is not preferable. Thus a preferred embodiment of the solid milk isthat t the amount ratio of crystalline lactose and amorphous lactose atthe surface 12 of the solid milk is 25:75 to 90:10. More specifically,the example of the amount of crystalline lactose at the surface area ofthe solid milk is 5 wt % to 50 wt %. The amount may be 10 wt % to 40 wt% and may be 10 wt % to 30 wt %.

Central area of the solid milk does not have to comprise muchcrystalline lactose. It is preferred for the central area of the solidmilk to comprise amorphous lactose. Namely it is preferred for the maincompound of the central area not to be amorphous lactose. Thus apreferred embodiment of the solid milk is that the center area 11 of thesolid milk does not contain crystalline lactose. The amount rate ofcrystalline lactose and amorphous lactose at the center area 11 of thesolid milk may be less than 90:10, namely the amount ratio ofcrystalline lactose and amorphous lactose is less than 1/9. Morespecific amount of crystalline lactose at the central area is 0 wt % to10 wt % and the amount may be less than 5 wt % and may be less than 4 wt%.

The solid milk of the present invention has crystalline lactose at thesurface area. The strength of solid milk increases when the layer thatcomprises crystalline lactose has thickness more than predeterminedvalue. Thus a preferred embodiment of the solid milk is that the solidmilk has 0.2 mm or more (preferably 0.5 mm or more) of a hard layer atthe surface 12 of the solid milk. The hard layer of the solid milk maycomprise more than 10 wt % of crystalline lactose. When the solid milkhas a hard layer which comprises crystalline lactose more than 0.2 mm,the solid milk has high enough strength. As explained above, thepreferred embodiment of the solid milk is that the region that includesthe central area is not a hard layer. Thus the examples of the thicknessof the hard layer are 0.2 mm to 2 mm and 0.5 mm to 2 mm. The thicknessof the hard layer may be 0.3 mm to 1.8 mm, the thickness may be 0.5 mmto 1.8 mm, or the thickness may be 0.7 mm to 1.5 mm.

A preferred embodiment of the solid milk is that the volume of the solidmilk is from 1 cm³ to 50 cm³. This solid milk has larger volume thanthat of powdered milk and it makes easy to calculate suitable amount ofthe solid milk and it makes solid milk to be convenient to betransported.

A preferred embodiment of the solid milk is that when a force, which iscaused by a load, in the direction of short axis of the solid milkcausing the solid milk be broken is 30 N to 300 N when the solid milkhas a rectangular solid shape. The solid milk of the embodiment hassufficient strength and thus it is possible for the solid milk frombeing broken in transport. When solid milk has division line and thesolid milk has the above strength, it is possible to divide the solidmilk in accordance with the divide line.

A preferred embodiment of the solid milk is that the ingredient of thesolid milk consists only of powdered milk.

A preferred embodiment of the solid milk is that the solid milk isdissolved in a liquid the volume of the liquid increases 9.5 ml to 10.5ml (more specifically 10 ml) or 19.5 ml to 20.5 ml (more specifically 20ml).

In this specification, solid milk means a type of milk modified intosolid state at normal temperature. The solid milk specifically meanspowdered milk molded into a predetermined size and weight, whichrenders, when dissolved in water, the same substance as that of thepowdered milk dissolved in water. The example of the solid milk istablet type (solid state) milk. The solid milk is usually intended to begiven by infants after dissolving into hot water. Thus it is better forthe solid milk to have similar taste as mother milk. The solid milk maycomprise sugar except for lactose less than 10 wt %, or preferably lessthan 6 wt %.

In this specification, crystalline lactose means monohydrate crystallinelactose and anhydrous crystalline lactose. The examples of crystallinelactose are alpha-type monohydrate crystalline lactose, alpha-typeanhydrous crystalline lactose, and beta type anhydrous crystallinelactose. Usually alpha-type anhydrous crystalline lactose is notdetected from powdered milk and solid milk. Thus crystalline lactosesubstantially means alpha-type monohydrate crystalline lactose and betatype anhydrous crystalline lactose.

In this specification, main peak means the most intense peak within thepredetermined range in the X-ray diffraction pattern.

In the specification, surface area or surface means that surface planesexcept for the bottle plane of solid milk or compressed powdered milk.For example when the solid milk has rectangular solid shape, then thesurface area means the upper plane and side planes of the solid milk.This is because when steps of humidifying and drying are executed withthe solid milk or compressed powdered milk on a tray, it is not easy tohumidify or dry the bottle plane.

In the specification, central area means the area that comprises thecenter of gravity of solid milk. In assessing the crystal state of thecentral area, the region that includes the center of gravity and 20% ofupper and lower thickness and 20% of left and right thickness is treatedto be the central area. Then the volume of the central area was 1/125times of the total volume of the solid milk. In executing X-rayscattering analysis of the central area, the solid milk may be cut sothat the above region should be exposure or a part of the central pointof the solid milk may be removed to analysis. 20% of upper and lowerthickness and 20% of left and right thickness mean 20% of height, widthand depth.

In the specification, hard layer means the layer that comprise more than10 wt % of crystalline lactose. The hard layer may be formed, e.g., byhardening the surface of the compressed powdered milk through steps ofhumidifying and drying. The hard layer usually has the feature that itis harder than the compressed powdered milk before it is hardened, isnot sticky or has less adhesion, and crystalline lactose thereinattached to each other.

In the specification, A to B means equal to or more than A and equal toor less than B.

In the specification, porosity means a percentage of the volume ofinterstices accounting for the volume of powder mass (see e.g. Iyakuhinno Kaihatu (Development of Medicine) edited by Miyajima Kouichiro (Vol.15), Hirokawa Shoten 1989, Page 240). More specifically, it is a valuemeasured by porosity measurement for solid milk in a test example whichwill be described later.

In this specification, powdered milk means modified milk and the likewhich is dried and powdered mixture of fat-soluble component such asmilk fat and resin and watersoluble component such as water, sugar,protein (including peptide and amino acid), and mineral. Examples ofpowdered milk include whole milk powder, modified milk powder, creamypowder, and the like.

In this specification, additive means an agent or agents such as binder,disintegrant, lubricant, and leaven other than nutritional component

In this specification, substantially no additive is added means to usebasically only the powdered milk as the basic ingredient, where theadditive is equal to or less that 0.5% by weight (preferably 0.1% byweight or less) that is the amount that the additive has no effect onthe nutritional component. It is to be noted that in the presentinvention, it is preferable that only the powdered milk is used as thebasic ingredient and that no additive other than the powdered milk isused.

It is preferred for the solid milk of the present invention to have thehard layer that comprises crystalline lactose and the crystallinelactose attaches to each other and form a net shaped hard layer.Thereby, it is possible for the solid milk of the present invention toattain suitable strength. The present invention makes crystallinelactose to exist on the surface of the solid milk such that thesolubility as well as the strength of the solid milk increases. Further,when the solid milk is dissolved, hot water may enter into the holes orvacant space, which may be a net shaped, quickly. Thus the solid milkhas a high solubility. The hard layer at the surface area of the solidmilk of the present invention lessen the surface tack or adhesiveness ofsolid milk and thus the solid milk is easy to handle in retaining thesolid milk and in transporting the solid milk.

The hard layer comprises net shaped crystalline lactose in whichcrystalline lactose attached to other part of crystalline lactose. Thecrystalline lactose with connected net shape is formed when the surfacearea of solid milk or compressed milk is humidified and dried under thepredetermined condition. Then the amorphous of lactose near the surfacearea of the solid milk bridges and crystallized. In other word, even ifcrystalline lactose would be added to powdered milk, it is impossible toobtain net shaped crystalline lactose. The present invention can obtainnet shaped lactose crystal is the following steps. Powdered milk iscompressed. Next, dissolve amorphous lactose that exists close to thesurface of solid milk. Then the compressed powdered milk is dried suchthat the amorphous lactose is crystallized with the amorphous lactoseattached to each other and crystalline lactose is attached to eachother. When amorphous lactose comprises little amount of crystallinelactose, the crystal acts as a core of crystallization, it is possibleto accelerate the crystallization of the amorphous lactose. Thus it ispossible for the solid milk of the present invention to control thecrystallization of the amorphous lactose by adding predetermined amountof crystalline lactose into powdered milk which is an ingredient and toobtain suitable surface conditions. The suitable surface conditionsinclude it has thick hard layer, has a lot of minute holes, and has lessadhesiveness.

It is possible for the solid milk of the present invention to have oneor a plurality of hard layers at predetermined places. For example, itis possible to make only peripheral region of one specific plane of thesolid milk to be a hard layer. It is possible to make only peripheralregion of one specific side of the solid milk to be a hard layer. It ispossible to make only peripheral region of one specific vertex of thesolid milk to be a hard layer. The shape of the hard layer may belattice shape or checker-board shape.

A preferred embodiment of the solid milk of the present invention has alot of vacant spaces or holes. A picture of SEM, scanning electronmicroscope, of the cut surface of the solid milk of the presentinvention shows that a hard layer is observed at the surface area to beshell like shape and powdered milk is observed to have walnut shapewithin the hard layer. Further, plenty of minute vacant spaces and holesin the hard layer are observed and relatively large vacant spaces andholes are observed within the hard layer. When the surface of the solidmilk is observed by SEM, concaves and convexes are observed as ifislands on the sea and plenty of vacant spaces and holes are observed.The preferred color of the solid milk is white or blight yellow. Thepreferred solid milk has no fume or has little smell.

The solid milk of the present invention has porosity of 30%-50% (between30% and 50% inclusive). As the porosity increases the solubilityincreases but the strength decreases. Also, when the porosity is small,the solubility is low. The porosity is mainly controlled by thecompression force in the compression process. It is to be noted that inthe present invention, while the porosity may be 35% to 50%, theporosity may be adjusted to 30% to 35%, 30% to 45%, 40% to 45%, or 40%to 50%, according to its intended purpose. By adjusting the porosity tobe within these ranges, it is made possible to obtain favorable solidmilk having resolved the problems of an oil off and the like as will bedescribed later.

It is preferable that plurality of interstices (vacant spaces or holes)exist in solid milk. The interstices (hollows) are preferablydistributed evenly. Since the interstices are distributed almost evenlyin the solid milk, higher solubility can be obtained. The larger theinterstice, the easier the water can penetrate, so that fast solubilitycan be obtained. On the other hand, when the size of the interstice istoo big, the strength is decreased or the surface of the solid milkbecomes rough. Therefore, the example of the size of the interstice is10 micrometers to 500 micrometers and preferred size is 50 micrometersto 300 micrometers. This size of the interstice can be measured withknown means, such as an examination of the surface and the cross-sectionplane of the solid milk by using a scanning electron microscope.

The components of the solid milk is basically the same as those of thepowdered milk which is the basic ingredient excluding the amount ofwater. The examples of components of the solid milk are sugar, protein,mineral, and water. The example of the fat content in the solid milk is5% to 70% by weight, the preferable fat content is 5% to 50% by weigh,and more preferable fat content is 10% to 45% by weight.

The solid milk of the present inventions may include the emulsified fatand the free fat as the fat. Namely, in the conventional powdered milkand the solid milk, the free fat has been proactively excluded due tothe problems of degrading flavor and floating on water (oil off) whendissolved in hot water. Preferably, the solid milk of the presentinvention proactively includes this free fat for an effective use assubstitute for the lubricant and the like. Thus, the present inventioncan produce good solid milk without using additives. However, too muchfree fat may result in problem of the oil off. Therefore, the example ofthe free fat content in the solid milk of the present invention is 0.5%to 4% by weight, preferable free fat content is 0.7% to 3% by weight,and more preferable free fat content is 1% to 2.5% by weight. This isbecause a preferable strength, solubility, and excessive oil off can becontrolled as shown in the embodiments which will be described later. Itis to be noted that the amount of free fat where the oil off will becomeproblematic depends on the physicality such as the fat composition andthe spherical form of fat within the powdered milk used as the basicingredient, so that the amount of the free fat included in the solidmilk may be appropriately adjusted within the above-mentioned ranges.

When there is much water contained in the solid milk, the storagestability degrades while scarce water makes the solid milk fragile.Therefore, the example of water content in the solid milk of the presentinvention is 1% to 4% by weight, and preferable water content is 2% to3.5% by weight.

The shape of the solid milk of the present invention is not specificallylimited as long as the solid milk has a certain size. The examples ofthe shape of the solid milk are column-shaped, elliptical column-shaped,cubic-shaped, rectangular parallelepiped-shaped, plate-shaped,sphere-shaped, polygonal column-shaped, polygonal pyramid-shaped,frustum of pyramid-shaped, and polyhedron. The column-shaped orquadrangular prism-shaped is preferable from the viewpoint ofportability convenience. In order to avoid situation that the solid milkbreaks, the corners are preferably chamfered.

The solid milk of the present invention preferably makes a quantity ofmilk to be drunk at one time when one to several particles of solid milk(preferably one particle of solid milk) are dissolved in hot water.Therefore, the example of the volume of the solid milk is 1 cm³ to 50cm³, the preferable volume is 2 cm³ to 30 cm³, and more preferablevolume is 4 cm³ to 20 cm³.

The solid milk of the present invention needs to have a certain level ofsolubility. The example of solubility for the solid milk of the presentinvention is less than 10 g or non dissolved remaining under themeasurement condition of solubility which will be described later, andpreferably less than 8 g and more preferably less than 4 g.

The solid milk of the present invention needs to have a high strength inorder to avoid as much as possible situation where the solid milk breakswhile being transported. For the solid milk of the present inventionunder the measurement condition of strength which will be describedlater, one having strength of 40 N or more is preferable. More preferredembodiment of the solid milk has 50 N or more of strength. On the otherhand, from the perspective of solubility, strength of 300 N or less ispreferable.

It is preferred for the solid milk of the present invention to haveadhesion ability less than 10 N so as to avoid solid milk sticking to atray after steps of humidifying and drying and so as to easily beremoved even if the solid milk were to attach to a tray. By lesseningadhesion ability of solid milk, it is possible to lessen trouble inmanufacturing and can enhance productivity per unit time.

2. Manufacturing Process

The method for manufacturing a solid milk of the present inventionincludes a compression step, a humidifying step and a drying step. Thecompression step is a step for compressing powdered milk to obtain asolid form of compressed powdered milk. The humidifying step is a stepfor humidifying the compressed powdered milk obtained by the compressionstep. The drying step is a step for drying the compressed powdered milkhumidified by the humidifying step. The humidifying step and the dryingstep make a part of the surface portion of the compressed powdered milkto be crystallized.

2.1 Compression Step

The compression step is a step for compressing a powdered milk to obtainsolid form of compressed powdered milk. In the compression step, thepowdered milk is compressed with relatively low pressure to the extentthat the powdered milk can be moved over to the next step. Thecompressed powdered milk has vacant space or interstices for water toenter the compressed milk. In the compression step, the powdered milk iscompressed in order to fulfill the requirements that compressed powderedmilk has appropriate interstices and can keep or retain its shape. Theporosity of the compressed powdered milk in this compression step isclosely related to the porosity of the solid milk. Further, if thelubrication of the compressed powdered milk is scarce, the compressedpowdered milk may attach to the apparatus such as a tablet machine.Moreover, if the compressed powdered milk has week shape keepingability, the solid milk than cannot keep good shape sometimes beproduced.

For the basic ingredient of the compression process, preferably onlypowdered milk is used and no additive is preferably and substantiallyadded. The powdered milk may be purchased commercially or the powderedmilk may be produced by the known producing method (such as theproducing method disclosed in, e.g., Japanese Patent ApplicationLaid-Open Publication Nos. HEI10-262553, HEI11-178506, 2000-41576,2001-128615, 2003-180244, and 2003-245039). The composition of thepowdered milk may be similar to that of the above-mentioned solid milk.It is to be noted that as the basic ingredient in the compressionprocess, fat may be added. However, if the fat is added, the fat maycause the oil off trouble. Further, the added fat sticks to the surfaceof the powdered milk. It decreases the precision of filling to themortar. Therefore, in the compression stage, the powdered milk which ismade to include a target free fat content is preferably used.

When the fat content in the powdered milk is large, the smallcompression force may be sufficient. On the other hand, when the fatcontent in the powdered milk is small, large compression force may berequired. Therefore, the use of powdered milk with more fat contentsatisfies the requirement for providing appropriate interstices andproducing compressed powdered milk with shape retaining attribute. Fromsuch viewpoints, the example of the fat content in the powdered milk is5 wt % to 70 wt %, preferably 5 wt % to 50 wt %, and more preferably 10wt % to 45 wt %.

As described above, the powdered milk which includes free fat ispreferable. In the present invention, this free fat is effectively usedinstead of lubricant or the like. Accordingly, the present invention canproduce good solid milk without adding additives. The example of freefat content in the solid milk of the present invention is 0.5 wt % to 3wt %, preferably is 0.7 wt % to 2.4 wt %, and more preferably is 1 wt %to 2 wt %.

When large amount of water is included in the powdered milk, the solidmilk has poor storage stability. When the amount of the water is small,the solid milk becomes fragile or brittle (the solid milk has poor theshape retention ability). Therefore, the example of the content of waterin the solid milk is 1 wt % to 4 wt %, preferably is 2 wt % to 3.5 wt %.

In the compression process, the compressed powdered milk is produced bycompression means for compressing the powdered milk to obtain compressedpowdered milk of the solid state. The compression means is notspecifically limited as long as being capable of compressing thepowdered milk to obtain the compressed powdered milk of the solid state.The examples of the compression means are a tablet machine such as aknown tablet machine and a compression test apparatus. Within theapparatus, the tablet machine is preferred. It is to be noted that theexamples of the tablet machines are described in Japanese ExaminedPatent Application Publication No. SHO33-9237, Japanese PatentApplication Laid-Open Publication No. SHO53-59066, Japanese PatentApplication Laid-Open Publication Nos. HEI6-218028, 2000-95674, andJapanese Patent No. 2650493.

It is to be noted that when using the tablet machine to compresspowdered object, for example, the powdered object is put in a mortar,pound with a pestle to add compression force to the powdered object, andmade into solid state. If the powdered object has scarce lubricity, thesituation may occur where the powdered object sticks to the surface ofthe pestle. This will not only degrade the quality of the product butwill require cleaning of the surface of the pestle, resulting in thedecrease of the process yield. Therefore, addition of lubricant isperformed especially in manufacturing medicine. However, the lubricantis wax that is not very soluble in water. Therefore, it is undesirableto add lubricant to such thing as the solid milk that is for drinking ina state dissolved in hot water. This is one of the reasons why themanufacturing of the solid milk has been difficult. The presentinvention, as described above, uses as the lubricant an adequate amountof the free fat that has been regarded as desirable not to be generated,thereby preventing the situation where the powdered milk sticks to thepestle. Moreover, as described above, by obtaining the powdered milkcompressed having an appropriate porosity, it is made possible to obtainsolid milk with an excellent shape retaining attribute, Also, while theaddition of disintegrant may cause a situation where sediment isgenerated, with the method for making the solid milk of the presentinvention, the disintegrant is unnecessary, so that such situation canbe effectively avoided.

The environmental temperature in the compression process is notspecifically limited. The compression process can be performed at theroom temperature. More specifically, the example of for theenvironmental temperature in the compression process is 10 degreesCelsius to 30 degrees Celsius. The example of humidity in thecompression process is 30% RH to 50% RH. It is preferable in thecompression process that the compression of the powdered milk isperformed continuously.

2.2. Humidification Process

Humidification process is a step of humidifying compressed powdered milkobtained at the step of compressing powdered milk. In the process, thecompressed powdered milk is put on a tray and is exposure under humidity60% RH to 100% RH for 5 seconds to 1 hour. Humidifying compressedpowdered milk makes granules at the surface of the compressed powderedmilk, especially a part of amorphous lactose, to be dissolved and tobring cross linking reactions. Because humidity will not reach innerportion of the compressed powdered milk, the technical effect of addinghumidity is limited to the surface of the compressed powdered milk.Namely, at the surface area, a part of amorphous lactose dissolves.Contrarily, amorphous lactose at the central area hardly or rarelydissolves. Thus the difference makes surface area and central areadifferent.

In the humidifying process, it is possible to humidify the compressedpowdered milk by the humidifying means for humidifying the compressedpowdered milk. The example of the humidifying means includes knownhumidifying means such as high humidity chamber, spray, and steam. Also,the example of humidifying method is one of the known humidifyingmethods that include placing the object under high humidity condition,misting the object with water by a spray, and spraying steam on theobject can be adopted. The examples of the humidity in the high humidityenvironment is 60% RH to 100% RH, preferably is 80% RH to 100% RH, andmore preferably 90% RH to 100% RH. Further, the examples of timeduration to place the object under the high humidity environment is 5seconds to 1 hour, preferably is 10 seconds to 20 minutes, and morepreferably is 15 seconds to 15 minutes. The example of the temperaturein the method of placing the object under high humidity environment is30 degrees Celsius to 100 degrees Celsius, and preferably is 40 degreesCelsius −80 degrees Celsius. The humidifying time duration may beappropriately adjusted according to the humidity, temperature, therequired physicality of the solid milk, and the like. When the solidmilk has cubit shape the side length of which is more than 1 cm and whenthe volume of the solid milk is 1 cm³ to 50 cm³, the preferred conditionmay be 60% RH to 100% RH, 5 seconds to 1 hour and 30 degrees Celsius to100 degrees Celsius.

The amount of water added (hereinafter, also referred to as humidifyingamount) to the compressed powdered milk in the humidifying process maybe appropriately adjusted. However, in the present invention, since onlythe powdered milk is basically used as the basic ingredient, asindicated by the embodiment (embodiment 5) and FIG. 3 that will bedescribed later, the following range is preferable as the humidifyingamount. Namely, while the humidifying amount of 0.5% increases thestrength, the humidifying amount of 1% almost doubles the strength.Thus, the strength tends to increase as the humidifying amountincreases. On the other hand, the increase of the strength stops withthe humidifying amount of 2.5% or more. Also, when the humidifyingamount exceeds 3%, the compressed powdered milk dissolves, becomesdeformed, or sticks to the apparatus during transfer. Accordingly, forthe amount of water added to the compressed powdered milk, 0.5% to 3% ofthe mass of the compressed powdered milk is preferable, while 1% to 2.5%is more preferable.

2.3. Drying Process

The drying process is a step of drying powdered milk that has beenhumidified at the humidification process on a tray, for example. Thedrying process makes humidified compressed powdered milk to be dried. Atthat time, when dissolved amorphous lactose near the surface area driesit become crystalline. By controlling the condition of drying it ispossible to obtain a hard layer that was formed by crystalline lactoseattached each other in a manner that forms net shape. It makes thestrength of surface area of the compressed powdered milk increased.

The hard layer manufactured the above has plenty of vacant spaces(holes) conformed by the net shaped crystalline lactose. Thus when thesolid milk is dissolved in hot water, the hot water enters into thevacant space (hole) and it brings favorable quick dissolubility. Themanufacturing method of the present invention can make it possible tomanufacture solid milk that has high strength and favorable solubility.Further, when solid milk comprises a hard layer with crystalline lactoseat its surface, it is possible to lessen surface tack or lessenstickiness. It leads the solid milk be retained as a product easily andbe handled easily, for example when it is transported. Previously, thereexisted solid milk that was attached to a tray after drying step wasover. The method of manufacturing solid milk of the present inventionprevents such situation from happening and even if solid milk were toattach to a tray it would be easy to remove it.

At the drying process it is possible to apply conventional method evenif the method can dry the compressed powdered milk humidified at thehumidifying process. The examples of the method are, putting the targetunder low humidity and high temperature circumstance and attaching driedair or high temperature dried to the target.

For the humidity in the method for placing the object under environmentof low humidity and high temperature, 0% RH to 30% RH, preferablehumidity is 0% RH to 25% RH, and more preferable humidity is 0% RH to20% RH. Thus, it is preferable to set the humidity as low as possible.For the temperature in the method for placing the object under anenvironment of low humidity and high temperature, and the example of thehigh temperature is 20 degrees Celsius to 150 degrees Celsius,preferable temperature is 30 degrees Celsius to 100 degrees Celsius, andmore preferable temperature is 40 degrees Celsius to 80 degrees Celsius.For the drying time in the method for placing the object underenvironment of low humidity and high temperature, the example is 0.2 minto 2 hours, preferable example is 0.5 min to 1 hour, and more preferableexample is 1 minute to 30 minutes.

As described above, if much water is included in the solid milk, theshelf life is degraded, while if the water is less it becomes fragile.Therefore, in the drying process, it is preferable to control the watercontent in the solid milk to be within 1% below and above (preferablywithin 0.5% below and above) the water content in the powdered milk usedas the basic ingredient by controlling the conditions such as dryingtemperature and drying time.

The humidifying step and the drying step can make a part of amorphouslactose around the surface of the compressed powdered milk to becomecrystalline. By crystallizing a part of amorphous lactose though thehumidifying step and the drying step, rather than just addingcrystalline lactose to powdered milk, it becomes possible to attain highstrength by binding crystalline lactose each other to form uniformedcrystal. Because the compressed powdered milk comprises powdered milkthat has large amount of amorphous lactose inside, it is possible tokeep favorable solubility by making use of vacant spaces and holed ofcompressed powdered milk. Thus it is possible to obtain solid milk thathas high strength and favorable solubility.

It is preferred for the powdered milk, which is used as ingredient, tocomprise more than 30 wt % of lactose. The more preferred amount oflactose is 40 wt %. It is preferred for the powdered milk to comprisemore than 20 wt % of amorphous lactose. The more preferred amount oflactose is 30 wt % or more and further preferred amount is 40 wt % ormore. When powdered milk comprise less than 30 wt % of lactose or lessthan 20 wt % of amorphous lactose, little amorphous lactose dissolvesthough the humidifying step and the drying step. Then the thickness ofthe hard layer, which is formed after the drying step, is not sufficientand the obtained solid milk might not have enough strength.

It is preferred for the powdered milk, which is ingredient, to comprise0.5 to 10 wt % of crystalline lactose. The small amount of crystallinelactose mixed in the powdered milk acts as cores for crystallization andit promote crystallization of amorphous lactose. Then the number ofminute holes at the surface of the solid milk increases and it becomespossible to reduce adhesives. When powdered milk comprise less than 0.5wt % of crystalline lactose, a hard layer that has enough thickness isdifficult to obtain because the amount of core for crystallization isnot sufficient. When the powdered milk comprises more than 10 wt % ofcrystalline lactose, the solubility of solid milk may not sufficientbecause the powdered milk has too much crystalline lactose.

The examples of method for mixing crystalline lactose into powderedmilk, which is ingredient, are:

(1) adding crystalline lactose into powdered milk;

(2) humidifying and drying granules of powdered milk so that crystallinelactose becomes mixed in powdered milk;

(3) Cooling concentrated milk before spray dry step, which is a one stepwithin manufacturing steps of powdered milk, so that crystalline lactosebecomes mixed in powdered milk.

Preferred amount of lactose crystal in the method of (1) and (2), it ispreferred that 0.5 to 2 wt % of crystalline lactose is mixed, and in themethod of (3), it is preferred that 0.5 to 10 wt % of crystallinelactose is mixed. The difference or non-uniformity of the surface ofgranules of crystalline lactose brings the difference among methods.

It is possible to select solid milk of the present invention, byanalyzing the amount of crystalline lactose at the surface such thatonly solid milk that comprises predetermined amount of crystallinelactose is selected to be a final product.

3. Method of Making Powdered Milk and Solid Milk

The method of making the powdered milk and the solid milk of the presentinvention includes a process of making powdered milk, and a process ofmaking solid milk by using the powdered milk as the basic ingredient. Itis to be noted that a part of the powdered milk made in the process ofmaking powdered milk may be used as powdered milk to be filled directlyin a container. Thus, the powdered milk and the solid milk can beobtained.

3.1 Method of Making Powdered Milk

Details of the manufacturing process of the powdered milk differdepending on the types of the manufactured articles such as powderedskimmed milk, modified milk represented by powdered milk for infants.Basically however, the powdered milk can be made by the process of basicingredient(adjustment)->clarification->sterilization->concentration->(homogenization)->spraydrying->sieving->filling. It is to be noted that the size of thepowdered milk after spray drying assumes about 5 micrometers to 150micrometers, and the size of the granulated substance of the powderedmilk assumes about 100 micrometers to 500 micrometers. Also, in thestate where the powdered milk and its granulated substance are mixed,the interstice assumes about 5 micrometers to 150 micrometers.

The example of the basic ingredient of the powdered milk is milk. Forthe milk, the example of milk is bovine milk, and more specifically,milk of a cow (Holstein, Jersey, etc.), a goat, a ewe, a buffalo, andthe like. The fat content can be adjusted by removing a part of fat fromthe milk by the method of centrifugal separation or the like. Also, thefollowing nutritional components can be added. On the other hand, whenmaking modified powdered milk, the following nutritional components areadded to the water and mixed to be used.

The powdered milk can be made by the processing the above-mentionedliquid as the ingredient by the known manufacturing method includingprocesses of clarification, sterilization, concentration, spray drying,sieving, and filling.

For the protein as the basic ingredient of the powdered milk, milkprotein and milk protein fraction such as casein, milk serum protein(alpha-lactalbumin, betalactoglobulin, and the like), milk serum proteinconcentrate (WPC), milk serum protein isolate (WPI); animal protein suchas egg protein; plant protein such as soy protein and wheat protein;peptide having the foregoing protein decomposed into variety of chainlengths by enzyme or the like; amino acid such as taurine, cystine,cysteine, arginine, and glutamine may be used alone or by mixture.

For the fat as the basic ingredient of the powdered milk, animal oil andfat such as milk fat, lard, beef fat, fish oil; vegetable oil such assoy oil, canola oil, corn oil, coconut oil, palm oil, palm kernel oil,safflower oil, cottonseed oil, linseed oil, and MCT; or fractional oil,hydrogenated oil, or ester exchanged oil of the foregoing oil may beused alone or by mixture.

For the carbohydrate as the basic ingredient of the powdered milk,lactin, simple sugar, glucose, malt sugar, oligosaccharide such asgalacto-oligosaccharide, fructooligosaccharide, lactulose,polysaccharide such as farina, soluble polysaccharide, and dextrin, orartificial sweetener may be used alone or by mixture. In addition,vitamin group, mineral group, aroma chemical, flavoring substance, orthe like may be added as the basic ingredient of the powdered milk.

3.1.1. Clarification Process

The clarification step is for removing microscopic foreign substanceincluded in cow milk or the like by known means such as centrifugalseparator, filter, or the like.

3.1.2. Sterilization Process

The sterilization process is for deadening microbe such as bacteriaincluded in cow milk or the like. The deadening temperature and holdingtime in the sterilization process vary depending on the types of thepowdered milk, and conditions related to the known sterilization can beadopted.

3.1.3. Concentration Process

The concentration process is an arbitrary process for preparatoryconcentrating milk or the like before the spray drying process whichwill be described later, and known means such as vacuum evaporative canand conditions can be adopted.

3.1.4. Homogenization Process

The homogenization process is an arbitrary process for homogenizing thesize of solid component such as fat globule distributed within cow milkor the like to fixed size, and known means and conditions for applyinghigh pressure to the processed liquid so as to pass the processed liquidthrough a narrow gap.

3.1.5. Spray Drying Process

The spray drying process is for obtaining fine particles by evaporatingthe water within the concentrated milk. A known means such as spraydryer and known condition can be adopted.

3.1.6. Sieving Process

The sieving process is for removing particles whose diameter is largesuch as hardpacked powder by passing the fine particles obtained by thespray drying process through sieves for particle size regulation.

3.1.7. Filling Process

The filling process is for filling the powdered milk in bags, cans, andthe like. For the method of making the powdered milk and the solid milkof the present invention, the above-mentioned method of making solidmilk may be adopted after making the powdered milk as mentioned above.Namely, the above-mentioned compression process may be performed usingthe powdered milk having passed through the above-mentioned sievingprocess as the basic ingredient.

4. Usage of Solid Milk

The solid milk of the present invention is generally dissolved in hotwater for drinking. More specifically, after pouring hot water in acovered container, particles of the solid milk of the present inventionas required are put in. Then, preferably the container is lightly shakenin order to quickly dissolve the solid milk for drinking in the state ofappropriate temperature.

While embodiments are shown hereinafter and the feature of the presentinvention will be described, the present invention is not limited tothese embodiments. In the following description, methods for evaluatingitems to be evaluated in the embodiments will be described beforedescribing reference examples and embodiments.

Test Example 1 Amount of Lactose Crystal and Amorphous Lactose

1. Quantitative Analysis of Total Lactose in a Sample

Quantitative analysis of total lactose in a sample was executed by meansof High Performance Liquid Chromatography. Column (Shodex NH2P-20 innerdiameter: 4 mm, length: 250 mm) was used. The phases were separatedusing 75% Acetonitrile (flow rate: 1 mL/min) as moving phase.Differential refractometer was used to detect targets. We calculatedtotal amount of lactose in a sample by a comparison of the peak area ofsample solution and lactose in aqueous solution of known concentrationof lactose.

2. Quantitative Analysis of Lactose Crystal in Sample

2-1. Preparation of Standard (The Physical Mixture of Known Amount ofLactose Crystal and Powdered Milk)

Milk powder with no crystal and alpha-monohydrate crystalline lactose(manufactured by Wako Pure Chemical Industries, special grade) orbeta-anhydrous crystalline lactose (SIGMA-made, 99%) was picked intostainless steel beaker with the amount indicated in the Table 1. Thepowdered ingredients were well mixed by means of spatula with a care soas not to grain powder. The mixture was passed through a 16 mesh sieve(mesh: 1000 micron openings). The mesh treatment was repeated 10 timesso that the mixture has uniform scale and standard 5, 10, 20, 40% ofcrystalline lactose (Physically mixed) was obtained. We confirmed thatno alpha-anhydrous crystalline lactose was detected from powdered milkand solid milk.

TABLE 1 Amount of α-type monohydrate β-type anhydrate crystallinecrystalline lactose crystalline lactose lactose Lactose Powdered LactosePowdered [wt %] [g] milk [g] [g] milk [g] 5 2.5 47.5 2.5 47.5 10 5 45 545 20 10 40 10 40 40 20 30 20 30

2-2. X-Ray Powder Diffraction

X-ray powder diffraction apparatus (XRD-type manufactured by ShimadzuCorporation 6100) was used for X-ray powder diffraction analysis. Wetook standard powder and sample powder by an aluminum plate (diameter 25mm, depth of 1 mm) and we attached them to the sample holder. Weobtained X-ray diffraction pattern by using X-ray source (Cu tube, Cu Kaline, 40 kV-30 mA, using Curved graphite Monochromator). We directlyattach solid milk to the sample holder and we analyzed it. As a typicalmeasurement conditions were the scanning conditions (two consecutivescans/min, 0.02 degrees step, the scanning angle of 5 to 40 degrees),and slit conditions (Divergence slit: 1 degrees, Scatter slit: 1degrees, Receiving slit: 0.3 mm).

2-3. Analysis of Diffraction Peak

FIGS. 2( a) and 2(b) show diffraction pattern of standard crystallinelactose (alpha type monohydrate crystalline lactose and beta typeanhydrous crystalline lactose).

In the diffraction pattern, regarding the peak of 2theta=12.5 degrees(which derives from alpha type monohydrate crystalline lactose) and thepeak of 2theta=10.5 degrees (which derives from beta anhydrous lactosecrystal), we executed smoothing and deducted base or back groundcomponents and then we calculate the integrated intensity obtained inthe region the width of which is twice of half width of full maximum ofthe peak. Using the ratio of the integral intensity of standard and thatof samples, we calculated the amount of alpha type monohydratecrystalline lactose and beta type anhydrous crystalline lactose in asample. The integral intensity is based on the integral of areas undereach peak. To compare the ratio roughly, it is possible to use theheight of peaks. Because the widths of peaks are almost uniform, theratio of peak heights is almost the same as the ratio of integratedintensities of two peaks.

3. Quantitative Analysis of Amorphous Lactose in a Sample

We calculated amorphous lactose in a sample in the following equation.Amorphous lactose in a sample=total lactose-crystalline lactose (alphatype monohydrate crystalline lactose and beta type anhydrous crystallinelactose)

Test Example 2 Evaluation of Strength

We calculated strength of solid milk and compressed powdered milk, whichis prehardened solid milk, by means of the load cell type tabletstrength tester manufactured by Okada Seiko Co. We prepared rectangularsolid shape of solid milk and compressed powdered milk and made thefracture pin (width 1 mm) of the strength tester push them at constantspeed of 0.5 mm/s in a direction of short axis of the rectangular solid.The strength was measured as load [N] when solid milk or compressedpowdered milk broken. We regarded strength (tablet strength) [N] ofsolid milk and compressed powdered milk as the obtained load [N].

Test Example 3 Evaluation of Solubility

Quantitative analysis for solubility of solid milk was executed. Twopieces of solid milk (11.2 g) were poured into a baby bottle. Then 80 g(80 mL) of hot water (test solution) was poured into the baby bottle toobtain liquid with 14 wt % of concentration of solute and kept theliquid in calm for 10 seconds. Then, we boiled the liquid for 5 secondwith rotating the baby bottle relatively mildly by hand so that thetrajectory of the baby bottle became a circle (4 revolutions persecond). After 5 seconds passed, all of the contents in the babblybottle were poured onto the mess, the weight of which had already known.The 32 mesh with openings of 500 micrometers was used. We measured theweight [g] of non-dissolved remaining, which was not dissolved by thehot water, on the mesh. First we wiped out the surface of thenon-dissolved remaining and the surface of the mess with care so thatthe non-dissolved remaining on the mesh would not drop out from themess. Next we measured the total weight of mesh and non-dissolvedremaining. Then we calculated the difference between the total weightand the weight of the mesh to obtain the weight of the non-dissolvedremaining on the mesh. Based on the test method, when the weight of thenon-dissolved remaining is light then the solid milk has an excellentsolubility.

Test Example 4 Porosity Measurement for Solid Milk

We measured the porosity of solid milk based on the following equation.

Porosity (%)=(1−W/PV)*100

In the above equation, W means the weight of solid milk or compressedpowdered milk (g), P means the density of solid milk or compressedpowdered milk measured using Beckmann pneumatic density meter (g/cm³),and V means the volume [cm³] of the solid milk or compressed powderedmilk calculated by the thickness measured by a micro meter and the shape(width and depth) of mold (mortar).

Test Example 5 Evaluation of Adhesive

Immediately after humidifying and drying solid milk on a tray, weevaluated the force required to remove the solid milk from the tray bymeans of Digital Force Gage (FGP-5) manufactured by Nihon Densan Shimpo.

Reference Example 1 Making Powdered Milk

The various powdered milk including various components as shown in table2 were prepared from the mixture of liquid with fat, sugar, protein,milk, and mineral group added to water and executed homogenization,concentration (evaporation), and spray drying in this order.

TABLE 2 Composition Powdered milk 1 Powdered milk 2 Protein [wt %] 15 12Fat [wt %] 18 26 Sugar [wt %] 60 57 Lactose in suger [wt %] 43 51 Ash[wt %]  4  2 Water, other [wt %]  3  3

Reference Example 2 Manufacturing of Solid Milk

In the step of humidifying compressed powdered milk, we used Combi Oven,FCCM6, manufactured by Fujimak Corporation as a humidifier. Wemaintained the temperature within the humidifier to be 65 degreesCelsius and humidity of 100% RH. We kept the compressed powdered milkfor 45 seconds (humidifying duration) under the condition. In the stepof drying the humidified compressed powdered milk, we used an airthermostat DK600 manufactured by Yamato Scientific Co., Ltd as a dryingmachine. In the step we dried the humidified compressed powdered milkfor 5 second under 95 degrees Celsius and humidity of 10% RH. Finally,we obtained solid milk.

Example 1 Technical Effect of Amorphous Lactose in Powdered Milk,Ingredient

We manufactured several solid milks that have different amount ofamorphous lactose that has composition of powdered milk 1 (total lactose43%). These solid milks had almost the same porosity. The strength ofsolid milk with 15.5% amorphous lactose was as low as 8 N, and that ofsolid milk with 43.0% amorphous lactose was 43 N (table 3). The resultof investigation by scanning electro micrometer, SEM, shows that bothsolid milks have different amount of bridging among granules. Generallyspeaking amorphous has higher solubility than that of crystalline. Weestimate that steam made amorphous lactose at the surface of thecompressed powdered milk dissolved once. Then the dissolved granulesattached each other to form bridges to enlarge the strength of the solidmilk. It shows that, in case of solid milk that has high porosity tohave high solubility, when the ingredient, powdered milk, comprisesamorphous lactose obtained solid milk has high strength (FIG. 3).

TABLE 3 Powdered milk Solid milk Po- Dis- Increased amount AmorphousCrystalline rosity Strength solved res- of crystalline lactose [wt]lactose [wt] [%] [N] idue [g] lactose [wt] 43 0 46.3 43 7 7.7 15.5 27.547.9  8 6.4 0

Example 2 Hardening by the Existence of Crystalline Lactose: SurfaceReforming and Increase Strength

We manufactured solid milks that have composition of powdered milk 2(total lactose 51%) using powdered milk 2A and 2B that have differentamount of crystalline lactose (table 4). During a step of preparing thepowdered milk, crystalline lactose precipitated. These solid milks hadalmost the same porosity. The strength of solid milks and evaluatedvalue of attaching ability (adhesiveness) were different drastically.These solid milks had different amount of crystalline lactose at theirsurface. The surface conditions of these solid milks investigated by SEMwere also different (FIG. 4).

FIG. 5 is a powdered X-ray diffraction spectrum regarding the solid milkmanufactured using powdered milk 2A of example 2. FIG. 6 is a powderedX-ray diffraction spectrum regarding the solid milk manufactured usingpowdered milk 2B of example 2. Both FIG. 5 and FIG. 6 show that, fromtop side, X-ray powder diffraction for surface area, 0.2 mm from thesurface, 0.5 mm from the surface, 0.7 mm from the surface, and 1.5 mmfrom the surface,

TABLE 4 Powdered milk 2A Powdered milk 2B Central area Amorphouslactose:   3%   0% Crystalline lactose:   48%   51% Total lactose:   51%  51% Surface Amorphous lactose:   28% (Increase: 28 − 3 = 25%)   13%(13 − 0 = 13%) Crystalline lactose:   23%   38% Total lactose:   51%  51% Whole of Porosity: 44.6% 43.9% solid milk Hardness: 61N 34NDissolved residue: 3.3 g 3.5 g Adhesion:  5N 25N

We measured the amount of lactose crystal of two pieces of solid milkmanufactured using powdered milk 2A and 2B at central area and surfacearea, which is within 0.5 mm from the surface. FIG. 7 is a graph thatshows a relationship between the distance from the surface and thecomprising ratio of crystalline lactose. As shown in FIG. 7, solid milkmade by powdered milk 2B comprises more than 10 wt % of crystallinelactose at the surface area. As shown in FIG. 7, at the point of 0.2 mmfrom the surface, solid milk made by powdered milk 2B comprises lessthan 5 wt % of crystalline lactose. As shown in FIG. 7, solid milk madeby powdered milk 2A had a hard layer with more than 1.5 mm thickness.The strength of solid milk made by powdered milk 2B was as low as 34 N,and the solid milk comprised little crystalline lactose at its surfaceand had a thin hard layer. Contrary, the solid milk made by powderedmilk 2A which comprises 3% of crystalline lactose had much crystallinelactose at its surface and had a thick hard layer and had strength of 61N. There was co-relationship between the amounts of crystalline lactoseat the surface area of solid milk, strictly speaking which relates toincreased amount of crystalline lactose; the amount of crystallizedlactose after amorphous lactose is melt, and strength. We think thatthis is because crystalline lactose in the powdered milk, which isingredient, acts as a core in crystallizing process and promotecrystallization of amorphous lactose.

Example 3 Technical Effect by the Existence of Crystalline Lactose 2:Surface Reforming

We manufactured three kinds of solid milk, each had porosity of 47%, byadding 0%, 0.5% and 2% of crystalline lactose (a type monohydratecrystalline lactose) to powdered milk 1 (total lactose 43%, crystallinelactose 0%, amorphous lactose 43%). We manufactured three kinds of solidmilk by adding 1% of crystalline lactose, 1% of glucose, 1% of dextrin,and 1% of calcium carbonate, respectively. FIG. 8 is a graph that showseffect of attachment with various amount of crystalline lactose. Solidmilk without adding crystalline lactose, which is the solid milk towhich 0% ofcrystalline lactose was added, to powdered milk 1 had as highattaching force (adhesion) as about 14.5 N and it was not easy to removethe solid milk from a tray. Further as shown in FIG. 10 m the conditionsof the surface of the solid milk was bad balance of bridging and minuteholes. On the contrary, solid milk made by powdered milk 1 with addedcrystalline lactose had less attaching force, as shown in FIG. 8,bridges and minute holes were detected at the surface of the solid milkas shown in FIG. 10. Attaching force of solid milk with added glucose,dextrin, or calcium carbonate were not lessen except for adding lactoseto the powdered milk 1 as shown in FIG. 9. This indicates that by makingmore than 0.5% of crystalline lactose existing in the powdered milk,which is ingredient, crystallization is accelerated and minute holes atthe surface increases and it is possible to lessen adhesiveness.

INDUSTRIAL APPLICABILITY

The solid milk of the present invention, when it is actuallymanufactured, is found to be suitable to be manufactured and marketed ascommercial products, the solid milk and the method of making the sameaccording to the present invention can be used in the foods industrysuch as alternative for the powdered milk and the method of making thesame.

EXPLANATION OF ELEMENT NUMERAL

-   -   11 central area    -   12 surface area

1. A solid milk, wherein the surface (12) of the solid milk has X-raydiffraction pattern that has a main peak of 2theta=10-15 degrees at2theta=10-11 degrees or at 2theta=12-13 degrees.
 2. The solid milk inaccordance with claim 1, wherein the peak at 2theta=10-11 degreesrelates to an anhydrous crystalline lactose, and wherein the peak at2theta=12-13 degrees relates to a monohydrate crystalline lactose. 3.The solid milk in accordance with claim 1, wherein the main peak of2theta=10-15 degrees is at 2theta=10.25-10.75 degrees or at2theta=12.25-12.75 degrees.
 4. The solid milk in accordance with claim1, wherein Ia/Ib is equal to or more than 2.5, wherein the Ia is a sumof: an integrated intensity of a first region of X-ray diffractionpattern of the surface (12) of the solid milk, the center of the firstregion is a main peak of 2theta=10-11 degrees of the pattern and thewidth of the first region is twice of the full width of half maximum ofsaid main peak of 2theta=10-11 degrees; and an integrated intensity of asecond region of X-ray diffraction pattern of the surface (12) of thesolid milk, the center of the second region is a main peak of2theta=12-13 degrees of the pattern and the width of the second regionis twice of the full width of half maximum of said main peak of2theta=12-13 degrees; and wherein the Ib is a sum of: an integratedintensity of a first region of X-ray diffraction pattern of center area(11) of the solid milk, the center of the first region is a main peak of2theta=10-11 degrees of the pattern and the width of the first region istwice of the full width of half maximum of said main peak of2theta=10-11 degrees; and an integrated intensity of a second region ofX-ray diffraction pattern of the center area (11) of the solid milk, thecenter of the second region is a main peak of 2theta=12-13 degrees ofthe pattern and the width of the second region is twice of the fullwidth of half maximum of said main peak of 2theta=12-13 degrees.
 5. Thesolid milk in accordance with claim 4, wherein the Ia/Ib is from 2.5 to15.
 6. The solid milk in accordance with claim 1, wherein the amount ofcrystalline lactose at the surface (12) of the solid milk is larger thanthat of crystalline lactose at center area (11) of the solid milk. 7.The solid milk in accordance with claim 1, wherein the amount ofcrystalline lactose at the surface (12) of the solid milk is more than 5wt % larger than that of crystalline lactose at center area (11) of thesolid milk.
 8. The solid milk in accordance with claim 1, wherein theamount ratio of crystalline lactose and amorphous lactose at the surface(12) of the solid milk is 25:75 to 90:10, and wherein center area (11)does not contain crystalline lactose or, the amount ratio of crystallinelactose and amorphous lactose at the center area (11) of the solid milkis less than 90:10.
 9. The solid milk in accordance with claim 1,wherein the solid milk has 0.2 mm or more of a hard layer at the surface(12) of the solid milk, and wherein the hard layer comprises more than10 wt % of crystalline lactose.
 10. The solid milk in accordance withclaim 1, wherein the volume of the solid milk is from 1 cm³ to 50 cm³.11. The solid milk in accordance with claim 1, wherein a force, which iscaused by a load, in the direction of short axis of the solid milkcausing the solid milk be broken is 30 N to 300 N when the solid milkhas a rectangular solid shape.
 12. The solid milk in accordance withclaim 1, wherein ingredient of the solid milk consist only of powderedmilk.
 13. The solid milk in accordance with claim 1, when the solid milkis dissolved in a liquid the volume of the liquid increases 9.5 ml to10.5 ml or 19.5 ml to 20.5 ml.
 14. A method for the manufacture of solidmilk, the method comprising steps of: compressing powdered milk so as toobtain solid compressed powdered milk; humidifying the compressedpowdered milk so as to obtain humidified compressed powdered milk; anddrying the humidified compressed powdered milk so as to obtain the solidmilk, wherein a part of amorphous lactose at the surface of the solidmilk (12) is crystallized at the steps of humidifying step and drying.15. The method for the manufacture of solid milk in accordance withclaim 14, wherein the surface of the solid milk (12) has X-raydiffraction pattern that has a main peak of 2theta=10-15 degrees at2theta=10-11 degrees or at 2theta=12-13 degrees.
 16. The method for themanufacture of solid milk in accordance with claim 14, wherein the stepof humidifying is a step for keeping the compressed powdered milk underhumidity of 60% RH to 100% RH atmosphere for 5 seconds to 1 hour, andwherein the step of drying is a step for keeping the humidified compresspowdered milk under humidity of 0% RH to 30% RH atmosphere for 0.2minute to 2 hours.
 17. The method for the manufacture of solid milk inaccordance with claim 14, wherein the powdered milk comprises more than30 wt % of lactose.
 18. The method for the manufacture of solid milk inaccordance with claim 14, wherein the powdered milk comprises more than20 wt % of amorphous lactose.
 19. The method for the manufacture ofsolid milk in accordance with claim 14, wherein the powdered milk doesnot contain any crystalline lactose or comprises less than 10 wt % ofcrystalline lactose.
 20. The method for the manufacture of solid milk inaccordance with claim 14, wherein the powdered milk comprises 0.5 wt %to 10 wt % of crystalline lactose.
 21. The method for the manufacture ofsolid milk in accordance with claim 14, wherein the powdered milkcomprises added crystalline lactose.
 22. The method for the manufactureof solid milk in accordance with claim 14, wherein the powdered milkobtains crystalline lactose by humidifying and drying granules ofingredients of the powdered milk.
 23. The method for the manufacture ofsolid milk in accordance with claim 14, wherein the method furthercomprises a step of cooling the concentrated milk before the step ofdrying such that the powdered milk obtains crystalline lactose.